Name Position Signature Date Prepared By C Cook Engineer C Cook 29/8/02 Concurred By Dr G Bacon Assistant Director Dr G Bacon 4/9/02

Transcription

1 TEST RESULT SHEET TITLE: Rolling resistance testing of 0 bicycle tyres MIRA Page of 5 MIRA Lt Watling Street, Nneaton Warwickshire, V0 0TU, UK Telephone: +44 (0) Facsiile: + 44 (0) Project No: lient: Inspire ycle Engineering Lt Test Date(s): 8-9th Jly 00 lient Liaison Engineer: Neil Selwoo Test Objectie/Metho/Specification No: The objectie of the test was to easre the coefficients of rolling resistance ( ) of 4 poplar 0 bicycle tyre types. The testing was perfore inoors in the MIRA crash laboratory on a san textre painte concrete floor. The test ehicle was the chassis of the Linley Special, MIRA s entry into the 00 Goowoo Soapbox hallenge, fitte with 4 tyres. The ehicle, of ass 00kg incling rier, was eqally loae on all 4 wheels an allowe to coast own for 43 between two ehicle spee easreent nits. Each set of tyres was teste at pressres of 80, 00 an 0 psi, for tests at each pressre caie ot an an aerage ale calclate. Data collecte fro MIRA s fll scale win tnnel testing of the Linley Special enables the coefficient of rolling resistance to be calclate for each tyre type. The rie height was kept constant between the ifferent section tyres to aintain the sae aeroynaic properties as the win tnnel testing. Specien Description/Part No(s): 4off Tioga op Pool 0 x.75 Tyres 4off Prio oet 0 x.75 Tyres 4off ontinental Gran Prix 0 x /8 Tyres 4off Schwalbe Stelio 0 x /8 Tyres Test Eqipent: off MIRA ehicle spee easreent nits. off PL Tyre inflator. off Salter ehicle weighing syste. off Linley Special chassis. Reslts: The Schwalbe Stelios were fon to hae the lowest rolling resistance of the types teste with a coefficient of rolling resistance of at 0psi. All the tyre types were fon to hae ecreasing rolling resistance with increasing pressre. The calclate coefficients are tablate in Tables -4 an plotte in Figre. The etho of calclation is escribe in Appenix A. Attachents/Notes: Tables to 4 - Tyre testing ata Figre - oefficients of rolling resistance for the teste tyre types at ifferent pressres Figre - The 'Linley Special Appenix A - alclation of oefficient of rolling resistance Appenix B Qality assrance nbers for calibrate eqipent. Nae Position Signatre Date Prepare By ook Engineer ook 9/8/0 once By Dr G Bacon Assistant Director Dr G Bacon 4/9/0 MIRA Lt 00. All rights resere, sbject to client contract. Inforation containe within this report ay not be pblishe in any for of aertising or other atter withot prior agreeent of the Managing Director of MIRA.

2 Inspire ycle Engineering Lt Rolling resistance testing of 0 bicycle tyres Pressre psi Initial Velocity ph Final Velocity ph Aerage Table - Schwalbe Stelio Data Pressre psi Initial Velocity ph Final Velocity ph Aerage Table - ontinental Gran Prix Data Pressre psi Initial Velocity ph Final Velocity ph Aerage Table 3 - Tioga op Pool Data Pressre psi Initial Velocity ph Final Velocity ph Aerage Table 4 - Prio oet Data MIRA Page of 5

3 Inspire ycle Engineering Lt Rolling resistance testing of 0 bicycle tyres oeffieicent of Rolling Resistance Schwalbe Stelio ontinental Gran Prix Tioga op Pool Prio oet Pressre (psi) Figre - oefficients of rolling resistance for the teste tyre types at ifferent pressres Figre - The 'Linley Special MIRA Page 3 of 5

4 Inspire ycle Engineering Lt Rolling resistance testing of 0 bicycle tyres Appenix A alclation of oefficient of rolling resistance Definition of ters: x = 43 = istance () a = acceleration (/s ) = 00kg = ass of ehicle (kg) ρ =.93kg/ 3 = ensity of air (kg/ 3 ) = rag coefficient A = frontal area of ehicle ( ) x A = (Of bare chassis with rier fro win tnnel testing) V = elocity (/s) = initial elocity (/s) = final elocity (/s) = coefficient of rolling resistance alclation: F = a = g ρ V V = g ρ x V V = x g + ρ V g + ρ ρ ρ g + ρ ln A ρ = ln A A( g( e = g + ρ g + ρ A g + ρ A e xρ A V V ) xρ A x 0 ) = x x = x = x MIRA Page 4 of 5

5 Inspire ycle Engineering Lt Rolling resistance testing of 0 bicycle tyres Appenix B Qality Assrance of Measreents The eans of calibrating test eqipent is checke on a reglar schele to traceable stanars in an International Assrance of Measreents (QAM) procere. Each ite of eqipent is isse with a QAM nber. The nbers for the eqipent se in these tests were: - Description MIRA Vehicle spee easreent nit MIRA Vehicle spee easreent nit Salter ehicle weighing syste PL Tyre Inflator QAM No. Q07899 Q079 Q030 Q0468 MIRA Page 5 of 5